Pope Benedict XVI called for Christians to unite behind the idea that marriage is between one man and one woman during a visit to Germany.

He described the Catholic Church's beliefs as facing a number of threats, and he included same-sex marriage on the list.

"Knowing, too, the value of family and marriage, we as Christians attach great importance to defending the integrity and the uniqueness of marriage between one man and one woman from any kind of misinterpretation," he said, according to the Associated Press. "Here the common engagement of Christians, including many Orthodox and Oriental Orthodox Christians, makes a valuable contribution to building up a society equipped for the future."

The pope appears to be interested in uniting faiths behind some commonalities in belief. He even visited the monastery where Martin Luther, who split devotees away from the church, once studied. Then the pope met with Muslim leaders and suggested that marriage might be among those areas where their religious interests are in common.

“I am thinking, for example, of the protection of the family based in marriage, respect for life in every phase of its natural course or the promotion of greater social justice,” he listed for the leaders, according to the New York Times.

His antigay stance on marriage is becoming a familiar refrain for the pope, who most recently reiterated his view during a visit to Madrid in August.

"The Lord calls many people to marriage, in which a man and a woman, in becoming one flesh, find fulfillment in a profound life of communion," he said in an address to youth.

As in Madrid, Pope Benedict's visit was also marked by protest, with the AP reporting that 9,000 were in the streets of downtown Berlin on Thursday. See images of the protests on the following pages.